Superior petrosal sinus connects it to the transverse
sinus or sigmoid.

Inferior petrosal sinuses connect it to the internal
jugular vein.

Extracranial communications

Superior and inferior ophthalmic veins.

The pterygoid venous plexus Via emissary veins.

The pharyngeal venous plexus.

Note that the facial vein communicates through the ophthalmic
veins and the pterygoid plexus.

Clinical
correlates on the cavernous venous sinus

Spread
of infections

Danger area of the face

Infections from here spread to cavernous sinus via opthalmic veins

Cavernous
sinus thrombosis

A
common effect of infection of in a venous sinus is thrombosis.
The risk is higher in the cavernous sinus due to the slow movement of
blood. The effects are usually:

Back-flow into the connecting
veins, for example ophthalmic veins leading to exopthalmos
and engorged conjuctiva (chemosis)

Compression of the nerves to
the extraocular muscles leading to ophthalmoplegia and impaired sensation in the area of supply of Cranial
V1 and V2.

Arteriovenous
fistula

This
may be produced by fractures of the bases of the skull, in which the
internal carotid artery tears within the cavernous sinus. Arterial blood
rushes in to the sinus, enlarging it and forcing blood out of it through
the communicating veins. This causes exophthalmos and chemosis
on the side of the injury. In these circumstances, the bulging
eye pulses in synchrony with the radial (or any other) pulse.
This condition is called pulsatile exophthalmos.

Others

Infections
spreading to the sinuses may affect the pituitary and the many cavernous
sinus communications may provide alternative routes for spread of malignancies.